Subcutaneous delivery tool

ABSTRACT

Subcutaneous implantation tools and methods of implanting a subcutaneous device using the same. The tool may include a tool body having a longitudinally extending recess having a distal opening and having a tunneler at a distal end of the tool body extending from the distal opening of the recess. The tool may include a plunger slidably fitting within at least a portion of the tool body recess. The recess may be configured to receive an implantable device and the tunneler preferably extends distally from the recess at a position laterally displaced from the device when the device is so located in the recess. Movement of the plunger distally within the recess advances the device distally out of the recess and alongside of and exterior to the tunneler.

This application is a Continuation of U.S. application Ser. No.14/204,227, filed Mar. 11, 2014, which claims the benefit of U.S.Provisional Application No. 61/788,940, filed Mar. 15, 2013, the entirecontent of each of which is hereby incorporated by reference.

BACKGROUND

The use of monitoring equipment to measure various physical parametersof a patient is well known. There is a growing demand for usingsubcutaneous monitoring devices, which allow doctors to obtaininformation without a patient being connected to an external machineand/or which may otherwise not be reproducible in office settings. Theterm subcutaneous generally implies locations within the body of apatient under the skin and exterior to the musculature beneath the skin.For example, an implantable device that includes the ability to monitora patient's heart beat in order to detect transient symptoms suggestingcardiac arrhythmia allows doctors to review data over a longer period oftime than using external monitoring equipment in a simulated testingsituation. However, to successfully implant implantable subcutaneousdevices an implantation tool should, for example, ensure that the deviceis not implanted in muscle, reduce contact between the surgeon and thewound, be used in an office setting to minimize patient discomfort andthe need for invasive surgery and have the ability to repeatedlyrecreate the same size incision site in the patient.

Exemplary prior art insertion tools include those illustrated in USPatent Application Publication No. 2010/0094252 by Wengreen, et al.,incorporated herein by reference in its entirety.

SUMMARY

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

Exemplary embodiments provide subcutaneous implantation tools andmethods of implanting a subcutaneous micro-device using the same. Theinvention provides a syringe-like tool, comprising a tool body,hereafter “handle”, having a hollow, distally longitudinally extendingrecess such as a bore or channel and having a distal opening throughwhich the device may be delivered. The device preferably also includes amovable plunger located within the bore or channel. An incision tool isprovided to make an incision through which the subcutaneous device isimplanted.

The device may, for example, be implanted in the region of the thorax. Aspecific recommended location will typically be provided within anassociated product manual. In one embodiment, two electrodes on the bodyof the device monitor the patient's subcutaneous ECG. The device may ECGrecordings in response to patient activation or in response toautomatically detected arrhythmias. Exemplary devices are disclosed inUS Patent Application Publication No. 2009/0036917 by Anderson, USPatent Application Publication No. 2010/0094252 by Wengreen, et al., USPatent Application Publication No. 2012/0283705 by Hoeppner, et al.,U.S. Pat. No. 5,987,352, issued to Klein, et al., U.S. Pat. Nos.6,412,490 and 7,035,684 issued to Lee, et al. and U.S. Pat. No6,230,059, issued to Duffin, et al., all incorporated herein byreference in their entireties.

The incision tool is designed to create an incision of repeatable widthand depth with a single motion. It is composed of a blade, designed tomake a repeatable incision, and handle, designed to ergonomically fitthe hand. The incision tool is intended to make the incision simple andrepeatable. Other mechanisms for making openings in the patient's skinsuch as trocars, spreaders, scalpels and the like may be substituted insome alternative embodiments.

The insertion tool delivers the device through the incision and into thesubcutaneous tissue. The tool is designed to ensure the device isdelivered into a tight pocket to maximize electrode contact with thesurrounding tissue in a highly repeatable manner, and is composed of twoparts: a handle and a plunger. The handle is composed of a bore orchannel section, used to hold the device and guide it during implant,and a protrusion extending distally of the channel, used to bluntlydissect an implant path for the device to travel down while beingimplanted. The tunneler extends distally from the channel a positionlaterally displaced from the device when the device is located in thechannel. The plunger is used to push the device distally out of thehandle, through the incision, alongside and exterior to the tunneler andalong the implant path created by the tunneler to the final implantlocation.

The device is typically loaded into the channel section of the insertiontool handle and sterile packaged along with both the insertion toolplunger and the incision tool.

The device is locatable within the channel distal to the plunger, sothat when the plunger is moved distally, the device advances distallyout of the tool body and into the tissue. Typically, the device willtake the form of an elongated body, having a length greater than itsthickness and width, as illustrated in the published Application No.2010/0094252, cited above. The device may extend along its longitudinalaxis between proximal and distal ends. The longitudinal channel or boreof the tool body may conform at least in part to the outer configurationof the device and more typically to a cross section of the device takenalong its longitudinal axis. If the device, like the above discusseddevice, has a width greater than its depth and/or is otherwise radiallyasymmetric around its longitudinal axis, this feature allows the deviceto be advanced into the tissue while maintaining a desired orientation,as discussed in more detail below.

Optimally, the final insertion site of the device is located a shortdistance from the incision site. As noted above, the handle ispreferably provided with an elongated protrusion or tunneler extendingdistally from the distal opening of the bore, which is insertable intothe tissue through the incision to create a path in the tissue, alongwhich the device may be advanced when pushed by the plunger. The distalend of the tunneler when so inserted is preferably located at thedesired location of the distal end of the device. The length of thetunneler is thus preferably at least equal to and preferably somewhatgreater than the length of the subcutaneous device.

Additional embodiments provide methods of implanting a subcutaneousmicro-device, including inserting the dissection body of the tooldescribed by the embodiments of the tool into an implantation site,where the dissection body includes a micro-device, and delivering themicro-device.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1-10 represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a perspective view of an exemplary implantable device and theassociated tool handle.

FIG. 2 is a perspective view of the exemplary implantable device.

FIG. 3 is a perspective view of the incision tool according to exemplaryembodiments.

FIGS. 4A, 4B and 4C are top, side and bottom views, respectively, of theincision tool of FIG. 3.

FIGS. 5A and 5B are perspective views of the tool handle and plunger,respectively, according to exemplary embodiments of the invention.

FIGS. 6A, 6B, 6C, 6D and 6E are distal end, cut-away, top, bottom andproximal end views, respectively, of the tool handle.

FIGS. 7A and 7B are cross sectional views through the tool handle asillustrated in FIG. 6C.

FIGS. 8A, 8B, 8C and 8D are distal end, cut-away, top and proximal endviews, respectively, of the plunger of 5B.

FIGS. 9A, 9B, and 9C are cross sectional, side and bottom views,respectively, of the plunger as illustrated in FIG. 8D.

FIG. 10 is a flow chart illustrating a method of delivering a device toa subcutaneous site according to exemplary embodiments.

DETAILED DESCRIPTION

Various exemplary embodiments will now be described more fully withreference to the accompanying drawings in which some exemplaryembodiments are illustrated. In the drawings, the thicknesses of layersand regions may be exaggerated for clarity.

Accordingly, while exemplary embodiments are capable of variousmodifications and alternative forms, embodiments thereof are shown byway of example in the drawings and will herein be described in detail.It should be understood, however, that there is no intent to limitexemplary embodiments to the particular forms disclosed, but on thecontrary, exemplary embodiments are to cover all modifications,equivalents, and alternatives falling within the scope of the invention.Like numbers refer to like elements throughout the description of thefigures.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of exemplary embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing onlyparticular embodiments and is not intended to be limiting of exemplaryembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Spatially relative terms, e.g., “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element or a relationship between a feature and anotherelement or feature as illustrated in the figures. It will be understoodthat the spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the Figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, for example, the term “below” can encompass both anorientation which is above as well as below. The device may be otherwiseoriented (rotated 90 degrees or viewed or referenced at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which exemplary embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Exemplary embodiments are directed to subcutaneous implantation toolsand methods of implanting subcutaneous micro-devices. FIGS. 1A to 10illustrate various exemplary embodiments of such subcutaneousimplantation tools.

FIG. 1 shows the implantable device 10, aligned longitudinally with thehandle 100, arranged for the insertion of device 10 into the channel 102of the handle 100. The proximal end 20 of the device is inserted intothe distal end 108 of the channel 102 of the handle and is advancedproximally until the proximal end 30 of the device is located adjacentan internal stop surface (not illustrated) within the handle 100. Atthis point, the distal end 20 of the device will be adjacent the distalend 108 of the handle 100. The open upper portion of the channel 102allows visual verification that the device 10 is properly inserted intothe channel. The tunneler 104 extends distally of the distal end 108 ofchannel 102. The distal end 106 of the tunneler is placed into theincision made by the incision tool with its upper surface facing outwardof the patient's body and advanced to provide blunt dissection of thesubcutaneous tissue to a point where the distal end 20 of the device isadjacent the opening of the incision. The handle 100 is then rotated 180degrees so that the tunneler 104 is then above the device (outwardrelative to the patient's skin). This allows upward pressure on thehandle to assist in temporarily enlarging the incision and assures thatthe device will not escape as advanced distally into the tissue. Thedevice 10 is then advanced by distal movement of the plunger illustratedin FIG. 5B within the channel 102 and along the tunneler 104 until it isproperly located within the tissue, displaced distally a short distancefrom the opening of the incision. The logo 112 assists in reminding thephysician to rotate the handle prior to insertion of the plunger andadvancement of the device.

FIG. 2 shows the device 10 in more detail. In this view it can be seenthat the device comprises two electrodes 12 and 14, located adjacent theproximal and distal ends, respectively, of the device. When implanted,electrode 12, located on the upper surface 16 of the device preferablyfaces outward toward the skin. As such, when the device is placed intothe handle as discussed above, the electrode 12 faces downward and isnot visible through the open upper portion of the channel, allowingverification of proper insertion into the handle.

The exemplary device 10 as illustrated generally takes the form of anelongated rectangular prism having rounded corners and a rounded distalend portion. The rounded distal end of the device assists in allowing itto advance into body tissue, providing blunt dissection of the tissue asit advances. Because the cross section of the device is substantiallygreater than the cross section of the tunneler, the device will belocated snugly within the tissue, reducing the chances for the formationof air bubbles adjacent the electrodes and also assisting in maintainingthe device in its desired position. The device has length (L), width (W)and depth (D) as illustrated. In this particular embodiment, the with isgreater than the depth, providing radial asymmetry along thelongitudinal axis of the device and assisting in maintaining the devicein its proper orientation with upper surface 16 facing outward afterimplant. A suture hole 18 may optionally be provided at the proximal endof the device to allow the physician to suture it to underlying tissueif desired. Projections 22 may optionally be provided to preventlongitudinal movement of the device after implant.

As discussed above, the inner surface of the channel of the handle ispreferably configured to correspond to the outer configuration of thedevice. As discussed below in more detail, the configuration of thechannel of the handle is configured to engage the rounded corners of thedevice, preventing rotation of the device within the handle.

FIG. 3 illustrates the incision tool 200, which is provided with acurved plastic handle 210 fitted with a flat, pointed blade 220 having awidth equal to the desired width of the incision. The handle is designedto be comfortably held in a position allowing the blade to be advancedthrough the skin at a shallow angle, avoiding damage to underlyingmuscle tissue.

FIGS. 4A, 4B and 4C show top, side and bottom views of the incisiondevice 200. As illustrated in 4A, both the differing coloration of thefinger grips 234 and 232 and the placement of the logo 236 on the uppersurface assist the physician in assuring that the orientation of theblade is correct to provide the desired shallow penetration angle.

FIGS. 5A and 5B show the handle 100 and the plunger 300 prior toinsertion of the plunger into the handle. After rotation of the handleso that its upper surface bearing marking 112 now faces inward towardthe patient's skin, the distal end 302 of plunger 300 is then insertedinto an opening in the proximal end 110 of the handle and into thechannel 102 of the handle.

The plunger is provided with a groove 306 running the length of thelower surface of the plunger up to a distal stop surface discussedbelow. The opening in the proximal end of the handle includes aprotrusion corresponding to the groove in the lower surface of theplunger, assuring its proper orientation within the handle. A marking308 adjacent the proximal end of the plunger assists the physician indetermining that the plunger is in the proper orientation for insertioninto the handle.

The plunger is advanced distally, pushing the device into the incisionalong the then inward facing surface of the tunneler. The device thusfollows the path defined by the tunneler to assure proper placementwithin the tissue. After insertion of the device, the handle and plungerare removed.

Various medical grade materials may be used to form the various parts ofthe subcutaneous implantation tool, for example, plastics, metals,rubber, sanitizable materials, etc. Exemplary embodiments of thesubcutaneous implantation tool may be inexpensive, disposable, etc. Thesubcutaneous implantation tool may also be configured to be used withknown automated injection systems, which use, e.g., compressed air orother inert gases in place of a manual plunger.

FIGS. 6A, 6B, 6C, 6D and 6E are distal end, cut-away, top, bottom andproximal end views, respectively, of the tool handle 100. In these viewsthe projection 114 is visible. Projection 114 provides a distal facingstop surface limiting the insertion of the device 10 into the channel102. It further engages the slot in the lower surface of the plunger300, assuring proper orientation of the plunger within the handle. Italso provides a proximal facing stop surface limiting distal movement ofthe plunger. The handle is also show as optionally provided with a slot116 in its lower surface, through which advancement of the plunger anddevice can be observed.

FIGS. 7A and 7B are cross sectional views through the tool handle asillustrated in FIG. 6C. In these views, the arrangement of the innercorner surfaces 12, 122, 124 and 126 can be seen. These surfaces, alongwith side surfaces 128 and 130, are arranged to generally correspond tothe corners and the side surfaces of the device, preventing rotation ofthe device within the handle. The distal facing surface of projection114 is also visible in this view.

FIGS. 8A, 8B, 8C and 8D are distal end, cut-away, top and proximal endviews, respectively, of the plunger of 5B. In these figures, theconfiguration of the groove 306 can be seen, along with distally facingstop surface 310, which engages with the proximal facing surface ofprotrusion 114 of the handle, to limit distal movement of the plunger.

FIGS. 9A, 9B, and 9C are cross sectional, side and bottom views.Respectively, of the plunger as illustrated in FIG. 8D. In these views,the configuration of the groove 306 is visible in more detail.

FIG. 10 is a flow chart illustrating a preferred embodiment of aninsertion process according to the present invention. At 500, theincision is made using the incision tool. At 510, the handle carryingthe device is inserted into the tissue such that the tunneler producesan elongated blunt incision along which the device may be advanced. Inthis step, the device is located outward of the tunneler relative to thepatient's body. At 520 the handle, carrying the device is rotated sothat the device is now inward of the tunneler relative to the patient'sbody. At 530, the device is advanced by the plunger along the handle andalong the then inward facing surface of the tunneler subcutaneously intothe patient's body. Finally, at 540, the handle and tunneler areremoved.

Exemplary embodiments thus described allow for subcutaneous implantationof devices that are minimally invasive. Note that exemplary embodimentsmay be used in both human and animal patients.

Exemplary embodiments of the present invention being thus described, itwill be obvious that the same may be varied in many ways. Suchvariations are not to be regarded as a departure from the spirit andscope of the exemplary embodiments of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the invention.

1-17. (canceled)
 18. An implantation tool for implanting a medicaldevice in subcutaneous tissue, the tool comprising: a tool body defininga longitudinal axis and a channel extending along the longitudinal axis,the channel having a distal opening, wherein the tool body is configuredto receive the medical device within the channel; and a plunger slidablyfitting within the channel and movable within the channel towards thedistal opening, wherein a distal end of the plunger is configured topush a proximal end of the medical device out of the channel through thedistal opening, wherein a portion of the channel is open to allowvisualization of at least a portion of at least one of the medicaldevice or the plunger within the channel from a position lateral to thetool body.
 19. The implantation tool of claim 18, wherein the tool bodydefines a projection into the channel, and wherein the plunger defines agroove that corresponds to and engages with the projection into thechannel.
 20. The implantation tool of claim 19, wherein the projectionand the groove are configured to limit longitudinal movement of theplunger within the channel.
 21. The implantation tool of claim 19,wherein the projection is located within the channel more proximal thanan entry point of the channel into which the medical device is received.22. The implantation tool of claim 19, wherein the projection is locatedat a proximal end of the tool body.
 23. The implantation tool of claim22, wherein the tool body defines the projection at a proximal openingof the channel.
 24. The implantation tool of claim 19, wherein theprojection and groove are configured to control an orientation of theplunger within the tool body.
 25. The implantation tool of claim 18,wherein a distal end of the implantation tool is configured for bluntdissection of the subcutaneous tissue.
 26. The implantation tool ofclaim 18, wherein the distal end of the plunger is movable distallybeyond the distal opening of the channel to displace the medical devicebeyond the distal opening of the channel.
 27. The implantation tool ofclaim 18, wherein the distal end of the plunger is movable distally todisplace a proximal end of the medical device a short distance from anincision into which the implantation tool is inserted.
 28. Theimplantation tool of claim 18, wherein the channel is configured toreceive an entire length of the medical device.
 29. The implantationtool of claim 18, wherein the tool body comprises a first portion thatis distal of the portion of the channel that is open and a secondportion that includes the portion of the channel that is open, wherein across-sectional size of the first portion is less than a cross-sectionalsize of the second portion.
 30. The implantation tool of claim 18,wherein the tool body defines a projection into the channel, wherein theprojection is located within the channel more proximal than an entrypoint of the channel into which the medical device is received, whereinthe plunger defines a groove that corresponds to and engages with theprojection into the channel, wherein the projection and the groove areconfigured to limit longitudinal movement of the plunger within thechannel, and wherein the distal end of the plunger is movable distallybeyond the distal opening of the channel to displace the medical devicebeyond the distal opening of the channel.
 31. The implantation tool ofclaim 18, wherein the tool body comprises a first portion that is distalof the portion of the channel that is open and a second portion thatincludes the portion of the channel that is open, wherein across-sectional size of the first portion is less than a cross-sectionalsize of the second portion, and wherein a distal end of the implantationtool is configured for blunt dissection of the subcutaneous tissue. 32.A kit comprising a medical device and an implantation tool forimplanting the medical device in subcutaneous tissue, the toolcomprising: a tool body defining a longitudinal axis and a channelextending along the longitudinal axis, the channel having a distalopening, wherein the tool body is configured to receive the medicaldevice within the channel; and a plunger slidably fitting within thechannel and movable within the channel towards the distal opening,wherein a distal end of the plunger is configured to push a proximal endof the medical device out of the channel through the distal opening,wherein a portion of the channel is open to allow visualization of atleast a portion of at least one of the medical device or the plungerwithin the channel from a position lateral to the tool body.
 33. The kitof claim 32, wherein a distal end of the implantation tool is configuredfor blunt dissection of the subcutaneous tissue.
 34. The kit of claim32, wherein the distal end of the plunger is movable distally beyond thedistal opening of the channel to displace the medical device beyond thedistal opening of the channel.
 35. The kit of claim 32, wherein themedical device comprises: an elongate device body, wherein a length ofthe device body is greater than a width of the device body, and thewidth of the device body is greater than twice a thickness of the devicebody; a first electrode proximate a distal end of the device body; and asecond electrode proximate a proximal end of the device body, wherein anouter configuration of the device body has the form of an elongatedrectangular prism having rounded corners, wherein the distal end of themedical device is rounded, wherein the channel is configured to engagethe rounded corners of the medical device to prevent rotation of themedical device within the channel, and wherein the medical device isconfigured to: monitor an electrocardiogram of a patient via theplurality of electrodes; detect a cardiac arrhythmia based on theelectrocardiogram; and record the electrocardiogram.
 36. The kit ofclaim 32, further comprising an incision tool configured to make anincision through which the implantation tool extends to deliver themedical device, wherein the incision tool comprises: a flat, pointedblade, wherein a width of the blade defines a width of the incision; anda curved handle connected to the blade, wherein the curved handle isdesigned to be held in a position allowing the blade to be advancethough skin and into the subcutaneous tissue at a shallow angle.
 37. Thekit of claim 32, wherein the tool body defines a projection into thechannel, wherein the projection is located within the channel moreproximal than an entry point of the channel into which the medicaldevice is received, wherein the plunger defines a groove thatcorresponds to and engages with the projection into the channel, whereinthe projection and the groove are configured to limit longitudinalmovement of the plunger within the channel, and wherein the distal endof the plunger is movable distally beyond the distal opening of thechannel to displace the medical device beyond the distal opening of thechannel.
 38. The kit of claim 32, wherein the tool body comprises afirst portion that is distal of the portion of the channel that is openand a second portion that includes the portion of the channel that isopen, wherein a cross-sectional size of the first portion is less than across-sectional size of the second portion, and wherein a distal end ofthe implantation tool is configured for blunt dissection of thesubcutaneous tissue.
 39. The kit of claim 32, further comprising anincision tool configured to make an incision through which theimplantation tool extends to deliver the medical device, wherein thedistal end of the plunger is movable distally beyond the distal openingof the channel to displace the medical device beyond the incision,wherein a distal end of the implantation tool is configured for bluntdissection of the subcutaneous tissue, wherein the tool body comprises afirst portion that is distal of the portion of the channel that is openand a second portion that includes the portion of the channel that isopen, wherein a cross-sectional size of the first portion is less than across-sectional size of the second portion, wherein the medical devicecomprises: an elongate device body, wherein a length of the device bodyis greater than a width of the device body, and the width of the devicebody is greater than a thickness of the device body; a first electrodeproximate a distal end of the device body; and a second electrodeproximate a proximal end of the device body, wherein the channel isconfigured to engage the medical device to prevent rotation of themedical device within the channel.
 40. The kit of claim 39, wherein theincision tool comprises a curved handle connected to a blade, whereinthe curved handle is designed to be held in a position allowing theblade to be advance though skin and into the subcutaneous tissue at ashallow angle.
 41. A method of implanting a medical device insubcutaneous tissue using an implantation tool, the implantation toolcomprising: a tool body defining a longitudinal axis and a channelextending along the longitudinal axis, the channel having a distalopening, wherein the tool body is configured to receive the medicaldevice within the channel, and wherein a distal end of the tool body isconfigured for blunt dissection of the subcutaneous tissue; and aplunger slidably fitting within the channel, wherein a portion of thechannel is open to allow visualization of at least a portion of at leastone of the medical device or the plunger within the channel from aposition lateral to the tool body, wherein the method comprises: makingan incision; inserting the medical device into the channel; tunnelingthe distal end of the implantation tool through subcutaneous tissue byat least blunt dissecting the subcutaneous tissue from the incision to afinal insertion site of the medical device; and moving a distal end ofthe plunger within the channel towards the distal opening to push aproximal end of the medical device out of the channel and into thesubcutaneous tissue through the distal opening.
 42. The method of claim41, wherein moving the plunger within the channel towards the distalopening comprises: moving the distal end of the plunger beyond thedistal opening of the channel; and displacing the medical device a shortdistance from the incision.
 43. The method of claim 41, wherein makingthe incision comprises making the incision at a shallow angle throughskin and into the subcutaneous tissue with a single motion using anincision tool separate from the implantation tool, the incision having arepeatable width and depth, the incision tool comprising: a flat,pointed blade, wherein a width of the blade defines the width of theincision; and a curved handle connected to the blade, wherein the curvedhandle is designed to be held in a position allowing the blade to beadvance though skin and into the subcutaneous tissue at the shallowangle.
 44. A kit comprising a medical device, an implantation tool forimplanting the medical device in subcutaneous tissue, and an incisiontool configured to make an incision through which the implantation toolextends to deliver the medical device, wherein the implantation toolcomprises: a tool body defining a longitudinal axis and a channelextending along the longitudinal axis, the channel having a distalopening, wherein the tool body is configured to receive the entirelength of the medical device within the channel; and a plunger slidablyfitting within the channel and movable within the channel towards thedistal opening, wherein a distal end of the plunger is configured topush a proximal end of the medical device out of the channel through thedistal opening, wherein the distal end of the plunger is movabledistally beyond the distal opening of the channel to displace themedical device beyond the distal opening of the channel, wherein adistal end of the implantation tool is configured for blunt dissectionof the subcutaneous tissue wherein a portion of the channel is open toallow visualization of at least a portion of at least one of the medicaldevice or the plunger within the channel from a position lateral to thetool body, and wherein the tool body comprises a first portion that isdistal of the portion of the channel that is open and a second portionthat includes the portion of the channel that is open, wherein across-sectional size of the first portion is less than a cross-sectionalsize of the second portion, wherein the medical device comprises: anelongate device body, wherein a length of the device body is greaterthan a width of the device body, and the width of the device body isgreater than twice a thickness of the device body; a first electrodeproximate a distal end of the device body; and a second electrodeproximate a proximal end of the device body, wherein an outerconfiguration of the device body has the form of an elongatedrectangular prism having rounded corners, wherein the distal end of themedical device is rounded, wherein the channel is configured to engagethe rounded corners of the medical device to prevent rotation of themedical device within the channel, and wherein the medical device isconfigured to: monitor an electrocardiogram of a patient via theplurality of electrodes; detect a cardiac arrhythmia based on theelectrocardiogram; and record the electrocardiogram, and wherein theincision tool comprises: a flat, pointed blade, wherein a width of theblade defines a width of the incision; and a curved handle connected tothe blade, wherein the curved handle is designed to be held in aposition allowing the blade to be advance though skin and into thesubcutaneous tissue at a shallow angle.